मुझे सच पता है।

Because this sentence uses a very common Hindi pattern:

X को / Xे + Y + पता है

Literally, it works like "To X, Y is known."

So:

• मुझे = to me
• सच = the truth
• पता है = is known / is معلوم

That is why Hindi says मुझे सच पता है, not मैं सच पता है.

This kind of structure is very common in Hindi for things like:

• मुझे पता है = I know
• उसे जवाब पता है = He/She knows the answer
• हमें रास्ता पता है = We know the way

So even though English says I know, Hindi often says something closer to The truth is known to me.

मुझे is the oblique form of मैं used in object/dative-style constructions. In everyday learning terms, you can think of it here as meaning:

• to me
• or simply me, in this sentence pattern

So:

• मैं = I
• मुझे = to me / me

In this sentence, मुझे is required because पता होना uses this structure.

Here सच means truth.

So in मुझे सच पता है, सच is the thing that is known: the truth.

Be careful, because सच can also appear in ways that feel closer to truly or really in other contexts, for example:

• सच? = Really? / Truly?
• यह सच है। = This is true.

But in your sentence, सच is a noun-like idea: the truth.

पता है means something like is known or is known to someone.

In everyday Hindi, पता होना is one of the main ways to say to know facts, information, answers, places, and so on.

Examples:

• मुझे पता है। = I know.
• तुम्हें उसका नाम पता है? = Do you know his name?
• उसे रास्ता पता नहीं है। = He/She does not know the way.

So in your sentence:

• मुझे सच पता है = I know the truth

Because है agrees with पता, not with मुझे.

This is easier to understand if you think of the sentence literally:

• मुझे = to me
• सच = the truth
• पता है = is known

So the main predicate is not I am, but rather known is.

That is why you get:

• पता है not
• पता हूँ

Similarly:

• मुझे यह बात पता है।
• उसे सब पता है।

In all of these, है is normal.

Yes, it is natural and correct.

However, Hindi has more than one way to express this idea, and the nuance can shift a little.

For example:

• मुझे सच पता है। = I know the truth.
• मैं सच जानता हूँ। = I know the truth.

The first one, with पता है, often sounds very natural for knowing information/facts.

The second one, with जानता हूँ, is also grammatical, but can sound a bit different depending on context. In many everyday situations, पता है is the more idiomatic choice for knowing a fact.

So if you are talking about information that someone knows, मुझे ... पता है is a very useful pattern.

This is a very common learner question.

A simple rule:

• पता होना is often used for knowing information, facts, answers, names, places, details
• जानना is a broader verb meaning to know, to be acquainted with, or to know about

Examples with पता होना:

• मुझे उसका नाम पता है। = I know his name.
• क्या तुम्हें समय पता है? = Do you know the time?
• हमें सच पता है। = We know the truth.

Examples with जानना:

• मैं उसे जानता हूँ। = I know him.
• मैं यह बात जानता हूँ। = I know this matter/fact.
• क्या आप गांधीजी के बारे में जानते हैं? = Do you know about Gandhi?

With truth/facts, both can work, but पता है often feels especially natural for having the information.

Yes. Hindi word order is flexible, although some orders sound more neutral than others.

The most neutral order here is:

• मुझे सच पता है।

You may also hear:

• सच मुझे पता है।
• मुझे पता है सच। — possible, but less neutral and more marked in normal conversation

Changing the order usually changes emphasis, not the core meaning.

For example:

• सच मुझे पता है। can emphasize the truth
• मुझे सच पता है। is the plain, natural version

As a learner, the safest choice is to use:

मुझे सच पता है।

Yes.

मुझे पता है simply means:

• I know
• I am aware
• I know that already

If the context already makes it clear what is being talked about, सच does not need to be stated.

So:

• मुझे सच पता है। = I know the truth.
• मुझे पता है। = I know.

They are related, but not always exactly identical in tone.

• सच = truth / true thing / what is true
• सच्चाई = truth, often with a slightly more formal or abstract feel

So you could also say:

• मुझे सच्चाई पता है।

But मुझे सच पता है is very natural and common.

In many contexts, सच sounds simpler and more direct, while सच्चाई can sound a bit heavier or more formal.

You add नहीं before पता है:

• मुझे सच नहीं पता है।

In everyday speech, people very often say:

• मुझे सच नहीं पता।

Both mean:

• I do not know the truth

The shorter version without the final है is very common in conversation.

A very common way is:

• क्या तुम्हें सच पता है? = Do you know the truth?
• क्या आपको सच पता है? = Do you know the truth? (polite/formal)

You can also ask more conversationally with intonation:

• तुम्हें सच पता है?

So to change the person:

• मुझे = to me
• तुम्हें = to you
• उसे = to him/her
• हमें = to us

A simple learner-friendly pronunciation guide would be:

mujhe sach pata hai

Roughly:

• मुझे ≈ moo-jhay / mujh-eh
• सच ≈ such but with a cleaner ch
• पता ≈ puh-taa
• है ≈ hai like high, though often shorter/lighter in connected speech

A natural rhythm is:

मुझे | सच | पता है

If spoken casually, it may sound smoother and faster than the careful written form.